| 摘要 |
A method of using measurements of the dc photocurrent produced by a photodetector to determine the wavelength or color of incident light, or to characterize certain properties of a semiconductor device or material. The intrinsic wavelength filtering ability of the photodetector is used as the basis for determining the wavelength of incident light by relating measurements of the dc photocurrent versus reverse bias voltage to the absorption coefficient of the semiconductor material from which the detector is fabricated. Color detection is accomplished by expressing the measured photocurrent as a linear combination of the photocurrents due to detection of each of the three primary colors. The coefficients of each of the terms of the linear combination are then varied to obtain the best fit to the measured photocurrent. This allows a determination of the color of the detected light based on the respective contributions of each of the primary colors to its actual color. The relationship between the absorption coefficient and wavelength can also be used to infer important characteristics of the semiconductor material from which the photodetector is fabricated. In this application of the method, monochromatic light of a known wavelength is used to illuminate the photodetector and measurements of the photocurrent versus reverse bias voltage are used to infer the value of the absorption coefficient corresponding to the wavelength of the light. These measurements can also be used infer the depletion width and doping density of the material.
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